1. Field of the Invention The present invention relates to a plug-in circuit board that is receivable in an electrical socket or receptacle. More particularly, the present invention relates to a male connector portion of such a circuit board that can be inserted into female shorting contacts contained in the socket or receptacle.
2. Description of the Related Art
Shorting contacts are electrical contacts that must, at any given time, either form a short circuit between the contacts or provide electrical contact with the connector portion of a plug-in circuit board that is inserted between the shorting contacts. In other words, it is undesirable to even momentarily open-circuit the shorting contacts while the circuit board is being inserted. Such an open-circuit condition, even if relatively brief, can cause disruptions in the operation of the electrical circuitry to which the shorting contacts are connected.
U.S. Pat. No. 5,088,931 to Niciolo et al., the entire contents of which are expressly incorporated herein by reference, addresses this problem by providing a notch in the connector portion of a plug-in circuit board so that the shorting contacts in the corresponding socket are not forced open until electrical contact is made with the circuit board. However, the Niciolo et al. patent does not address the problem of excessive insertion force that results when there are many shorting contacts which must engage the electrical contacts on the circuit board.
When inserting a plug-in circuit board into a socket or receptacle, it is desirable to have a low insertion force. Conventionally, the insertion edge of a circuit board is beveled to reduce insertion force when inserting the circuit board into the receptacle. Inserting a beveled card into a receptacle that has shorting contacts is problematic in that the shorting contacts are forced apart by the insulating material of the circuit board prior to connection to the metal contacts on the circuit board. Thus, beveling the insertion edge is not a solution to the problem of reducing insertion force when making contact with a large number of shorting contacts.
What is needed is a circuit board that can mate be connected to a large number of shorting contacts during insertion into a socket or receptacle without requiring that excessive insertion force be used. What is also needed is a circuit board that allows for sequential connections to be made between the electrical contacts on the circuit board and the shorting contacts of the socket or receptacle.
It is therefore an object of the present invention to overcome the problems that arise during insertion of a circuit board into a socket or receptacle when numerous shorting contacts are present in the receptacle.
It is also an object of the invention to provide a plug-in circuit board that will not disrupt the operation of electrical circuits in the connected equipment when numerous shorting contacts are being connected.
It is another object of the invention to provide a plug-in circuit board requiring low insertion force during insertion into a socket or receptacle when the socket or receptacle contains numerous shorting contacts.
It is yet another object of the invention to allow sequential electrical connections to be made between a plug-in circuit board and a socket or receptacle when numerous shorting contacts are involved.
It is still a further object of the invention to provide a plug-in circuit board that can be safely and easily installed and removed from a socket or receptacle that includes both shorting contacts and conventional contacts.
In accordance with one aspect of the present invention, a plug-in circuit board assembly comprises a circuit board made of an electrically insulating material with a plurality of electrical components mounted thereon, and a connector portion extending from one side of the circuit board and adapted to be inserted into a socket or receptacle when the circuit board assembly is moved in an insertion direction. The connector portion has a first insertion edge which extends substantially perpendicular to the insertion direction of the circuit board, and a second insertion edge which extends at an oblique angle with respect to the insertion direction of the circuit board. A first plurality of electrically conductive fingers are carried by the connector portion and extend toward the first insertion edge. A second plurality of electrically conductive fingers are also carried by the connector portion and extend toward the second insertion edge. The second insertion edge may be recessed with respect to the first insertion edge. The first insertion edge is preferably beveled, and the second insertion edge is preferably not beveled. The oblique angle is preferably between about 5 and 10 degrees. Preferably, at least one of the first plurality of conductive fingers does not extend to the first insertion edge, whereas each of the second plurality of electrically conductive fingers preferably extends to the second insertion edge. The connector portion may be integral with the circuit board, and a faceplate may be connected to the side of the circuit board opposite the connector portion.
In accordance with a second aspect of the present invention, a plug-in circuit board assembly comprises a circuit board made of an electrically insulating material with a plurality of electrical components mounted thereon, and a connector portion extending from one side of the circuit board and adapted to be inserted into a socket or receptacle when the circuit board assembly is moved in an insertion direction. The connector portion has a pair of end sections with beveled insertion edges that extend substantially perpendicular to the insertion direction of the circuit board, and a cut-out section located between the end sections. The cut-out section has at least one non-beveled insertion edge that extends at an oblique angle with respect to the insertion direction of the circuit board. A first plurality of electrically conductive fingers carried by the connector portion extends toward the beveled insertion edges of the end sections. A second plurality of electrically conductive fingers carried by the connector portion extends toward the non-beveled insertion edge of the cut-out section. Preferably, the oblique angle between the non-beveled insertion edge of the cut-out section and the insertion direction of the circuit board is between about 5 and 10 degrees. It is also preferred that at least some of the first plurality of electrically conductive fingers do not extend to the beveled insertion edges of the end sections, and that each of the second plurality of conductive fingers extends to the non-beveled edge of the cut-out section. The connector portion is preferably integral with the circuit board. The cut-out section may have a pair of non-beveled insertion edges which extend at opposite oblique angles with respect to the insertion direction of the circuit board, thereby forming a generally V-shaped recess in the connector portion. A faceplate may be connected to the side of the circuit board opposite the connector portion.